We turn to director michael bay's newest film. It's a departure from his blockbuster. "Pain & gain." It's based on a true life story. And he sad down with our amy robach. You made a grave mistake. Reporter: He's the leading man behind some of hollywood's biggest spectacles. High-energy films, with special effects and pyrotechnic mayhem. There you go. Yes. Reporter: And now, michael bay is taking on a dark action comedy with a twist. I watched a lot of movies, paul. I know what I'm doing. Reporter: The almost unbelievable "pain and gain" is a true story about ultrapumped up bodybuilders, behind an abduction, extortion scheme. When did you think thiould be a really good movie? I thought it was a real interesting take on life. Criminals looking for the american dream in all the wrong ways. An absurd, bizarre story. Reporter: Mark wahlberg and wade johnson play the muscle-headed criminals with a soft side. These guys are charming. They had a guy kidnapped. And then, had a loving wedding the next day. It's from the minds of the criminals. Reporter: Did you embellish the story a little bit? The strangest stuff is the true stuff in this movie. I'm back. Reporter: And to embody his character, wahlberg literally pumped up. I said, mark, you look like a little guy compared to duane. Duane's an anomaly. So, mark put on 40 pounds. Wow. These guys would eat chicken every two hours. Reporter: For "good morning america," amy robach, abc news, new york.

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